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Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology, characterized pathologically by α-synuclein aggregates preferentially found in oligodendroglial cells. DNA methylation has emerged as a mechanism of regulation of α-synuclein expression. Reduced 5-methylcytosine (5-mC) DNA methylation of α-synuclein has been found in the brains of patients with Parkinson’s disease (PD). 5-hydroxymethylcytosine (5-hmC) methylation is another epigenetic modification of DNA. It is involved in the de-methylation of DNA, gene regulation, and DNA repair mechanisms. Here, we examined sections of human paraffin-embedded brain tissue from the cerebellum and brain stem, including the substantia nigra pars compacta, of patients with PD (n = 8) and MSA (n = 8) as well as age-matched controls (n = 8). The neocortical tissue of PD patients (n = 10) and controls (n = 10) was also examined. Using immunohistochemistry, we analyzed the expression of 5-mC and 5-hmC with an automatic, rater-independent semi-quantification method. We found a significant upregulation of 5-mC, but not 5-hmC, in cortical sections from PD patients. The brain stem and substantia nigra, and in particular the dopaminergic neurons, showed unchanged levels of both 5-mC- and 5-hmC-immunoreactivity in all groups. In the cerebellum, 5-mC was significantly decreased only in MSA patients in the granule cell layer; in contrast, 5-hmC was significantly upregulated in the cerebellar white matter of both PD and MSA patients. Our study showed different levels of expression of total 5-mC and 5-hmC methylation across different brain regions in PD and for the first time in MSA. Our results indicate that 5-mC may be relevant in MSA. The underlying mechanism of the differential 5-mC and 5-hmC expression remains unclear.

Intracerebral hemorrhage (ICH) is a frequently disabling or fatal disease. The localizationof ICH often allows an etiological association. However, in atypical/lobar ICH, the cause of bleedingis less obvious. Therefore, we present prospective histopathological and radiological studies whichwere conducted within the diagnostic workup to identify causes for lobar ICH other than hypertension.From 2016 to 2018, 198 patients with spontaneous, non-traumatic ICH requiring neurosurgicalmonitoring were enrolled in an institutional prospective patient registry. Patients with deep-seatedICH and/or hemorrhagically transformed cerebral infarcts were excluded from further analysis.Data to evaluate the source of bleeding based on histopathological and/or radiological workup wereprospectively evaluated and analyzed. After applying the inclusion criteria and excluding patientswith incomplete diagnostic workup, a total of 52 consecutive patients with lobar ICH were furtheranalyzed. Macrovascular disease was detected in 14 patients with lobar ICH (27%). In 11 patients,diagnostic workup identified cerebral amyloid angiopathy-related ICH (21%). In addition, five patientswith tumor-related ICH (10%) and six patients with ICH based on infectious pathologies(11%) were identified. In four patients, the cause of bleeding remained unknown despite extensivediagnostic workup (8%). The present prospective registry study demonstrates a higher probabilityto identify a cause of bleeding other than hypertension in patients with lobar ICH. Therefore, athorough diagnostic work-up in patients with ICH is essential to accelerate treatment and furtherimprove outcome or prevent rebleeding

Ependymoma with YAP1-MAMLD1 fusion is a rare, recently described supratentorial neoplasm of childhood, with few cases published so far. We report on 15 pediatric patients with ependymomas carrying YAP1-MAMLD1 fusions, with their characteristic histopathology, immunophenotype and molecular/cytogenetic, radiological and clinical features. The YAP1-MAMLD1 fusion was documented by RT-PCR/Sanger sequencing, and tumor genomes were studied by molecular inversion probe (MIP) analysis. Significant copy number alterations were identified by GISTIC (Genomic Identification of Significant Targets in Cancer) analysis. All cases showed similar histopathological features including areas of high cellularity, presence of perivascular pseudo-rosettes, small to medium-sized nuclei with characteristic granular chromatin and strikingly abundant cells with dot-like cytoplasmic expression of epithelial membrane antigen. Eleven cases presented features of anaplasia, corresponding to WHO grade III. MRI showed large supratentorial multinodular tumors with cystic components, heterogeneous contrast enhancement, located in the ventricular or periventricular region. One of two variants of YAP1-MAMLD1 fusions was detected in all cases. The MIP genome profiles showed balanced profiles, with focal alterations of the YAP1 locus at 11q22.1-11q21.2 (7/14), MAMLD1 locus (Xp28) (10/14) and losses of chromosome arm 22q (5/14). Most patients were female (13/15) and younger than 3 years at diagnosis (12/15; median age, 8.2 months). Apart from one patient who died during surgery, all patients are alive without evidence of disease progression after receiving different treatment protocols, three without postoperative further treatment (median follow-up, 4.84 years). In this to date, largest series of ependymomas with YAP1-MAMLD1 fusions we show that they harbor characteristic histopathological, cytogenetic and imaging features, occur mostly in young girls under 3 years and are associated with good outcome. Therefore, this genetically defined neoplasm should be considered a distinct disease entity. The diagnosis should be confirmed by demonstration of the specific fusion. Further studies on large collaborative series are warranted to confirm our findings.

Allgrove or triple A syndrome is a rare autosomal recessive disorder that can present with a variable range of multi-system manifestations, including optic atrophy, cerebellar ataxia, upper and lower motoneuron signs and various neuropathic abnormalities. These cases are a diagnostic challenge, particularly when the eponymous combination of achalasia, Addisonianism and alacrima is incomplete. Therefore, it is in the differential diagnosis for multisystem conditions and should be known to pathologists who diagnose disorders of skeletal muscle. Here, we describe new findings in skeletal muscle histology from the case of a boy of consanguineous Turkish origin whose achalasia provided the only specific clinical clue to the diagnosis. These include myocyte nuclear abnormalities with partially abnormal anti-lamin A/C immunohistochemistry and altered nuclear ultrastructure but without overt abnormalities of nuclear pore morphology. In this case, the condition was associated with a hitherto unreported c.762delC mutation in the nucleoporin gene AAAS.

Atypical teratoid/rhabdoid tumor (ATRT) is a highly malignant brain tumor predominantly occurring in infants. Mutations of the SMARCB1 gene are the characteristic genetic lesion. SMARCB1-mutant tumors in adolescents and adults are rare and may show uncommon histopathological and clinical features. Here we report seven SMARCB1-deficient intracranial tumors sharing distinct clinical, histopathological and molecular features. Median age of the four females and three males was 40years (range 15–61years). All tumors were located in the pineal region. Histopathologically, these tumors displayed spindled and epithelioid cells embedded in a desmoplastic stroma alternating with a variable extent of a loose myxoid matrix. All cases showed loss of nuclear SMARCB1/INI1 protein expression, expression of EMA and CD34 was frequent and the Ki67/MIB1 proliferation index was low in the majority of cases (median 3%). Three cases displayed heterozygous SMARCB1 deletions and two cases a homozygous SMARCB1 deletion. On sequencing, one tumor showed a 2bp deletion in exon 4 (c.369_370del) and one a short duplication in exon 3 (c.237_276dup) both resulting in frameshift mutations. Most DNA methylation profiles were not classifiable using the Heidelberg Brain Tumor Classifier (version v11b4). By unsupervised t-SNE analysis and hierarchical clustering analysis, however, all tumors grouped closely together and showed similarities with ATRT-MYC. After a median observation period of 48months, three patients were alive with stable disease, whereas one patient experienced tumor progression and three patients had succumbed to disease. In conclusion, our series represents an entity with distinct clinical, histopathological and molecular features showing epigenetic similarities with ATRT-MYC. We propose the designation desmoplastic myxoid tumor (DMT), SMARCB1-mutant, for these tumors.

The original publication contains the following errors: In the title, the words ‘oligodendroglial cell-like’ should read ‘oligodendroglial-like’. (The correct title is shown in this erratum.) The images in Figs. 3 and 4 were incorrect. The correct figures are shown below. All the figure citations except the citation of Fig. 1 were incorrect. All citations of Fig. 2 actually concern Fig. 5, all citations of Fig. 3 actually concern Fig. 6, all citations of Fig. 4 actually concern Fig. 2, all citations of Fig. 5 actually concern Fig. 3 and all citations of Fig. 6 actually concern Fig. 4.

Primary Hodgkin's lymphomas of the central nervous system (CNS) as well as cerebral involvement as the first manifestation of a systemic Hodgkin's disease are very rare. CNS involvement usually occurs in patients with advanced or relapsing systemic disease. Because primary CNS Hodgkin's lymphoma may present unexpected and sometimes misleading clinical and neuroradiological features, the description of unusual cases is important for expanding the awareness of this rare disease of the central nervous system. We describe three cases of primary Hodgkin's lymphoma of the CNS with peculiar features. None of the three patients had a previous clinical history of systemic Hodgkin disease. Case 1 and case 2 presented an unusual localization in the cerebellar hemisphere and in the brainstem, respectively. The third case occurred as a temporal lesion in the settings of a Richter transformation of a chronic lymphocytic leukemia.

The post-translational modification of the neural cell adhesion molecule (NCAM) by polysialic acid (polySia) represents a remarkable example of dynamic modulation of homo- and heterophilic cell interactions by glycosylation. The synthesis of this unique carbohydrate polymer depends on the polysialyltransferases ST8SiaII and ST8SiaIV. Aiming to understand in more detail the contributions of ST8SiaII and ST8SiaIV to polySia biosynthesis in vivo, we used mutant mouse lines that differ in the number of functional polysialyltransferase alleles. The 1,2-diamino-4,5-methylenedioxybenzene method was used to qualitatively and quantitatively assess the polySia patterns. Similar to the wild-type genotype, long polySia chains (>50 residues) were detected in all genotypes expressing at least one functional polysialyltransferase allele. However, variant allelic combinations resulted in distinct alterations in the total amount of poly-Sia; the relative abundance of long, medium, and short polymers; and the ratio of polysialylated to non-polysialylated NCAM. In ST8SiaII-null mice, 45% of the brain NCAM was non-polysialylated, whereas a single functional allele of ST8SiaII was sufficient to polysialylate approximately 90% of the NCAM pool. Our data reveal a complex polysialylation pattern and show that, under in vivo conditions, the coordinated action of ST8SiaII and ST8SiaIV is crucial to fine-tune the amount and structure of polySia on NCAM.

Chordoid glioma of the third ventricle was recently reported as a novel tumor entity of the central nervous system with characteristic clinical and histopathological features (Brat et al., J Neuropathol Exp Neurol 57: 283–290, 1998). Here, we report on a histopathological, immunohistochemical and molecular genetic analysis of five cases of this rare neoplasm. All tumors were immunohistochemically investigated for the expression of various differentiation antigens, the proliferation marker Ki‐67, and a panel of selected proto‐oncogene and tumor suppressor gene products. These studies revealed a strong expression of GFAP, vimentin, and CD34. In addition, most tumors contained small fractions of neoplastic cells immunoreactive for epithelial membrane antigen, S‐100 protein, or cytokeratins. The percentage of Ki‐67 positive cells was generally low (< 5%). All tumors showed immunoreactivity for the epidermal growth factor receptor and schwan‐nomin/merlin. There was no nuclear accumulation of the p53, p21 (Waf‐1) and Mdm2 proteins. To examine genomic alterations associated with the development of chordoid gliomas, we screened 4 tumors by comparative genomic hybridization (CGH) analysis. No chromosomal imbalances were detected. More focussed molecular genetic analyses revealed neither aberrations of the TP53 and CDKN2A tumor suppressor genes nor amplification of the EGFR, CDK4, and M DM2 proto‐oncogenes. Our data strongly support the hypothesis that chordoid glioma of the third ventricle constitutes a novel tumor entity characterized by distinct morphological and immunohistochemical features, as well as a lack of chromosomal and genetic alterations commonly found in other types of gliomas or in meningiomas.

Intravascular diffuse large B-cell lymphoma limited to the CNS (cIVL) is a very rare malignant disorder characterized by a selective accumulation of neoplastic lymphocytes (usually B cells) within the lumen of CNS blood vessels but not in the brain parenchyma. In the past, treatment of cIVL with anthracycline-based regimens was unsatisfactory with very short survival times. In the case of cIVL presented here, high-dose methotrexate-based polychemotherapy according to the Bonn protocol plus rituximab therapy was successful and led to a complete clinical and MRI remission which is ongoing 29 months after diagnosis.

Epithelial differentiation in glioblastomas (GBM) may be associated with circumscribed growth and focal keratin expression resembling carcinoma metastasis. Therefore these rare lesions can pose a diagnostic problem suggesting coincidental occurrence of two separate neoplasms. However molecular analysis should succeed in establishing a common origin of seemingly unrelated tumor samples. Five GBMs exhibiting epithelial differentiation were microdissected and analyzed for mutations in the TP53 gene. SSCP analysis of exons 5-8 was followed by direct sequencing of aberrantly migrating fragments. TP53 mutations were identified in tumors from two of five patients. A G--T transversion in codon 176 was detected in a tumor, initially diagnosed as metastases of unknown origin, however, a later autopsy revealed GBM. In this lesion, the mutation was observed in both, areas of astrocytic differentiation and areas of epithelial differentiation. One tumor diagnosed as GBM with epithelial differentiation carried C--T transition in codon 211 in both, areas of astrocytic and epithelial differentiation. Thus, molecular analysis proved clonality in two GBMs with epithelial differentiation, thereby excluding a collision tumor. The present data support the concept of clonal origin of these morphologically heterogeneous lesions.

To present 58 cystic space-occupying formations of the spinal canal in 53 cases; these formations are called “juxtafacet cysts”. Fifty-Three patients (33 women and 20 men, with an average age of 60.8 years) were evaluated retrospectively by neurosurgery. All of the patients had received simple X-P, computed tomography (CT) and magnetic resonance imaging (MRI) before surgery. The neurological findings were evaluated on admission and in a follow-up review. Surgical intervention was performed on all patients and they underwent gross-total cyst removal. During surgery, the origin of a cyst was well observed. Follow-up data ranged from 6 to 46 months. Patient outcome was graded on a scale of excellent, good, or poor. Histological findings were evaluated. In 53 patients 58 cysts were identified. Four of the patients had multiple cysts. All cysts were associated with mobile spine. Fifty-five cysts were found in the lumbo-sacral region, two cysts were found in the cervico-thoracic region and one cyst in the thoracic region. Forty-two patients presented back pain and 52 patients presented radicular pain. Four patients had a cauda equina syndrome. Sensory disturbance was observed in 24 cases and motor weakness was observed in 21 cases. Claudication was observed in 19 cases. All cases with cervico-thoracic or thoracic cysts presented myelopathy. The duration of these clinical symptoms ranged from 10 days to 10 years. After surgery there was no case of a recurrent cyst during the follow-up period. Thirty-four cases had an excellent outcome, 18 a good outcome, and one a poor outcome. Out of 58 cysts 32 were joint cysts (11 synovial cysts, 21 ganglion cysts). A further 19 were flavum cysts, one was a posterior longitudinal ligament (PLL) cyst and six others were unknown pseudo cysts. In 34 of the cysts we found hemosiderin deposits and in eight amyloid deposits. Present investigation and findings in literature show a clear comparison of these cystic formations and the mobile part of the spine. An anatomical relation to a vertebral joint (“facet”) is only found in some of the cases (32 of 58). Further to that, the name “cyst” is not correct either, because most of the cystic formations are presented without a cell lining on their internal wall and therefore they are pseudo-cystic. We think that these cystic formations should be called “cystic formations of mobile spine” (CYFMOS) rather than “juxtafacet cysts”. A surgical intervention is the best treatment for these cysts if they cause a compression of nerve roots or/and of the spinal cord.

CASE OF THE MONTH: ABSTRACT April 2004: A 53-year-old woman presented with a large club-shaped intra- and extraspinal tumor of the C6 nerve root which had intradurally grown through the enlarged C5–6 neural foramen and focally infiltrated the dura mater. Microscopy revealed a melanin-pigmented tumor with spindle-shaped and epithelioid cells and scattered psammoma bodies, a so-called psammomatous melanotic schwannoma (PMS). More than half of the patients with PMS have Carney complex, a genetically heterogeneous multiple neoplasia syndrome of autosomal-dominant inheritance, which in our patient, however, could not be detected unequivocally. Prognosis of all melanotic schwannomas (MSs) is not good with local recurrences or metastases in over 40% of cases. In our case, frequent versicular nuclei with distinct nucleoli, occasional mitoses and apoptoses and increased focal MIB-1 labeling indices prompted us to diagnose a malignant PMS. However, histologic criteria for malignancy in MSs are not clearly defined and there is no reliable histopathological indicator of malignant clinical behavior in MSs. Therefore, designation of “PMS with malignant histologic features” may be more appropriate. Since tumor recurrences and metastases im MSs may occur after more than 5 years, long-term follow-up of affected patients is required. One year after operation our patient showed no signs of tumor recurrence or metastases.

BACKGROUND: The aim of this study was to investigate the potential of dynamic O-(2-[(18)F]fluoroethyl)-L-tyrosine ((18)F-FET) PET for differentiating local recurrent brain metastasis from radiation injury after radiotherapy since contrast-enhanced MRI often remains inconclusive.METHODS: Sixty-two patients (mean age, 55 ± 11 y) with single or multiple contrast-enhancing brain lesions (n = 76) on MRI after radiotherapy of brain metastases (predominantly stereotactic radiosurgery) were investigated with dynamic (18)F-FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) of (18)F-FET uptake were determined (20-40 min postinjection) as well as tracer uptake kinetics (ie, time-to-peak and slope of time-activity curves). Diagnoses were confirmed histologically (34%; 26 lesions in 25 patients) or by clinical follow-up (66%; 50 lesions in 37 patients). Diagnostic accuracies of PET parameters for the correct identification of recurrent brain metastasis were evaluated by receiver-operating-characteristic analyses or the chi-square test.RESULTS: TBRs were significantly higher in recurrent metastases (n = 36) than in radiation injuries (n = 40) (TBRmax 3.3 ± 1.0 vs 2.2 ± 0.4, P < .001; TBRmean 2.2 ± 0.4 vs 1.7 ± 0.3, P < .001). The highest accuracy (88%) for diagnosing local recurrent metastasis could be obtained with TBRs in combination with the slope of time-activity curves (P < .001).CONCLUSIONS: The results of this study confirm previous preliminary observations that the combined evaluation of the TBRs of (18)F-FET uptake and the slope of time-activity curves can differentiate local brain metastasis recurrence from radiation-induced changes with high accuracy. (18)F-FET PET may thus contribute significantly to the management of patients with brain metastases.

The arterial vascular wall contains a non-neuronal intrinsic cholinergic system. The rate-limiting step in acetylcholine (ACh) synthesis is choline uptake. A high-affinity choline transporter, CHT1, has recently been cloned from neural tissue and has been identified in epithelial cholinergic cells. Here we investigated its presence in rat and human arteries and in primary cell cultures of rat vascular cells (endothelial cells, smooth muscle cells, fibroblasts). CHT1-mRNA was detected in the arterial wall and in all isolated cell types by RT-PCR using five different CHT1-specific primer pairs. Antisera raised against amino acids 29-40 of the rat sequence labeled a single band (50 kD) in Western blots of rat aorta, and an additional higher molecular weight band appeared in the hippocampus. Immunohistochemistry demonstrated CHT1 immunoreactivity in endothelial and smooth muscle cells in situ and in all cultured cell types. A high-affinity [3H]-choline uptake mechanism sharing characteristics with neuronal high-affinity choline uptake, i.e., sensitivity to hemicholinium-3 and dependence on sodium, was demonstrated in rat thoracic aortic segments by microimager autoradiography. Expression of the high-affinity choline transporter CHT1 is a novel component of the intrinsic non-neuronal cholinergic system of the arterial vascular wall, predominantly in the intimal and medial layers.

BACKGROUND: Fusobacterium nucleatum is a strict anaerobic microorganism that causes disease entities such as periodontal and soft tissue abscesses, pulmonary and intraabdominal infections and very rarely intracerebral infections. CASE PRESENTATION: Here, we report the rare case of a previously healthy 25-year-old German man with a cerebellar abscess caused by Fusobacterium nucleatum that resulted in rapid brain death. Toxicological screening showed positivity for amphetamines and cannabis. The diagnosis was obtained by polymerase chain reaction amplification of bacterial deoxyribonucleic acid in cerebrospinal fluid. CONCLUSIONS: In drug users clinicians should think about rare causes of brain abscesses/meningitis. Early diagnosis is necessary and justifies the use of molecular techniques.